Describe the main principles of trichromatic theory. How does this theory explain color vision and color blindness?

Question

What will be an ideal response?

Answer 1

Trichromatic theory suggests that color perception is produced by three types of cone receptors in the retina that are particularly sensitive to different, but overlapping, ranges of wavelengths. The theory is based on experiments showing that a person with normal vision can match any color in the spectrum by combining three other wavelengths. Young and Helmholtz reasoned that if the combination of any three wavelengths of different intensities is indistinguishable from any single pure wavelength, the visual system must base its perception of color on the relative responses of three receptor systems-cones sensitive to red, blue, and green. The study of defective color vision, or color blindness, provides further support for the trichromatic theory. Complete color blindness is rare; most color-blind people, the vast majority of whom are men, can see some colors but not others. The nature of color blindness depends on which of the three kinds of cones is inoperative. The three cone systems are green, red, and blue. In the most common form of color blindness, the green cone system malfunctions in some way, rendering green indistinguishable from certain combinations of blue and red.